How do I tell a male from a female?

MALE

FEMALE

The testicles on the male rats are rather large and it is quite easy to tell the male from the female. In rats under 2-3 weeks of age, it is a little more difficult. Males reach sexual maturity as early as 5-6 weeks of age. Females at 9-12 weeks, but a female should not be bred till at least 12 weeks old at the very youngest.